KR102130207B1 - Organic solar cell - Google Patents

Abstract

This specification is the first electrode; A second electrode; And one or more organic material layers including a photoactive layer, wherein the photoactive layer includes an electron donor and an electron acceptor, and the electron donor is a first unit represented by Chemical Formula 1; A second unit represented by Formula 2; And a polymer comprising a third unit represented by Chemical Formula 3, wherein the electron acceptor relates to an organic solar cell comprising a non-fullerene compound.

Description

Organic solar cell {ORGANIC SOLAR CELL}

This application claims the filing date benefit of Korean Patent Application 10-2017-0079706 filed with the Korean Patent Office on June 23, 2017, the entire contents of which are incorporated herein.

This specification relates to an organic solar cell.

An organic solar cell is a device that can directly convert solar energy into electrical energy by applying a photovoltaic effect. Solar cells can be divided into inorganic solar cells and organic solar cells according to the materials constituting the thin film. Since conventional inorganic solar cells already show limitations in economical and material supply and demand, they are easy to process and inexpensive and have various functions. Organic solar cells are in the spotlight as a long-term alternative energy source.

It is important to increase the efficiency of the solar cell so that it can output as much electrical energy as possible from the solar energy. The fullerene compound, which is an existing electron acceptor material, has a low absorption rate in the visible light region and has low thermal stability. There is a problem.

Accordingly, many examples of organic solar cells using a non-fullerene compound as an electron acceptor material have been recently published, and their power conversion efficiency has been achieved to about 4% to 5.9%. However, since the non-fullerene-based compound currently shows good efficiency only in combination with a specific polymer, it has become an important task to find a new polymer capable of exhibiting a good efficiency with the non-fullerene-based compound.

Two-layer organic photovoltaic cell (C.W.Tang, Appl.Phys. Lett., 48, 183.(1986)) Efficiencies via Network of Internal Donor-Acceptor Heterojunctions (G. Yu, J. Gao, J. C. Hummelen, F. Wudl, A. J. Heeger, Science, 270, 1789. (1995))

The present specification aims to provide an organic solar cell.

An exemplary embodiment of the present specification is a first electrode; A second electrode provided to face the first electrode; And one or more organic material layers provided between the first electrode and the second electrode and including a photoactive layer, wherein the photoactive layer includes an electron donor and an electron acceptor, and the electron donor is represented by Formula 1 below. A first unit; A second unit represented by Formula 2 below; And a polymer comprising a third unit represented by the following Chemical Formula 3, wherein the electron acceptor includes a non-fullerene-based compound.

[Formula 1]

[Formula 2]

[Formula 3]

In Chemical Formulas 1 to 3,

X1 to X4 are the same as or different from each other, and each independently selected from the group consisting of CRR', NR, O, SiRR', PR, S, GeRR', Se and Te,

Y1 and Y2 are the same or different from each other, each independently selected from the group consisting of CR", N, SiR", P and GeR",

R, R', R", Q1 to Q4, R1 to R4, R10 and R11 are the same as or different from each other, and each independently hydrogen; deuterium; halogen group; nitrile group; nitro group; imide group; amide group; hydroxyl group; Substituted or unsubstituted alkyl group; substituted or unsubstituted cycloalkyl group; substituted or unsubstituted alkoxy group; substituted or unsubstituted aryloxy group; substituted or unsubstituted alkenyl group; substituted or unsubstituted aryl group; or substituted Or an unsubstituted heterocyclic group,

R20 and R21 are the same as or different from each other, and each independently a substituted or unsubstituted alkoxy group; Or a substituted or unsubstituted aryloxy group,

a and b are the same as or different from each other, and each is an integer from 1 to 3,

d and e are each an integer from 0 to 3,

When a, b, d, or e are each 2 or more, structures in 2 or more parentheses are the same or different from each other,

A1 to A4 are the same or different from each other, and each independently is hydrogen, fluorine or chlorine, and at least one of A1 to A4 is fluorine or chlorine.

The organic solar cell according to an exemplary embodiment of the present specification is excellent in thermal stability and power conversion efficiency by using the polymer as an electron donor and using the non-fullerene compound as an electron acceptor.

In addition, the polymer according to one embodiment of the present specification has a high HOMO energy level, and the organic solar cell including it as an electron donor of a photoactive layer has excellent open voltage characteristics.

1 is a view showing an organic solar cell according to an exemplary embodiment of the present specification.
2 is a view showing the current density according to the voltage of the organic solar cell of Examples 1-1 to 1-3.
3 is a view showing the current density according to the voltage of the organic solar cells of Comparative Examples 1 and 2.
4 is a diagram showing an NMR spectrum of Formula J synthesized in Preparation Example.
5 is a diagram showing an NMR spectrum of Formula J-1 synthesized in Preparation Example.
6 is a diagram showing an NMR spectrum of Formula K synthesized in Preparation Example.

Hereinafter, the present specification will be described in more detail.

In the present specification, the term “unit” refers to a repeating structure included in the polymer monomer, and refers to a structure in which the monomer is bound to the polymer by polymerization.

In the present specification, the meaning of'comprising units' means being included in the main chain in the polymer.

In the present specification, when a part “includes” a certain component, this means that other components may be further included rather than excluding other components, unless specifically stated to the contrary.

When a member is referred to as being'on' another member in the present specification, this includes not only the case where one member is in contact with the other member but also another member between the two members.

In the present specification, the energy level means the amount of energy. Therefore, even when the energy level is displayed in the negative (-) direction from the vacuum level, the energy level is interpreted to mean the absolute value of the corresponding energy value. For example, the HOMO energy level means the distance from the vacuum level to the highest occupied molecular orbital. In addition, the LUMO energy level means the distance from the vacuum level to the lowest unoccupied molecular orbital.

An exemplary embodiment of the present specification is a first electrode; A second electrode provided to face the first electrode; And one or more organic material layers provided between the first electrode and the second electrode and including a photoactive layer, wherein the photoactive layer includes an electron donor and an electron acceptor, and the electron donor is represented by Formula 1 A first unit; A second unit represented by Formula 2; And a polymer comprising a third unit represented by Chemical Formula 3, wherein the electron acceptor includes a non-fullerene-based compound.

In the photoactive layer of the organic solar cell, an electron donor and an electron acceptor absorb light to form an exiton, and the generated exciton moves to the interface between the electron donor and the electron acceptor to separate into electrons and holes, and the electron to the electron acceptor In accordance with, holes move to each electrode along the electron donor to generate an electric current. At this time, how well the morphology of the electron donor and the electron acceptor is formed electrically has a decisive effect on the generation of current, and the polymer is particularly well formed with a non-fullerene compound and a morphology, resulting in organic The efficiency of the solar cell can be increased.

Examples of the substituents are described below, but are not limited thereto.

The term'substitution' means that the hydrogen atom bonded to the carbon atom of the compound is replaced with another substituent, and the position to be substituted is not limited to a position where the hydrogen atom is substituted, that is, a position where the substituent can be substituted, and when two or more are substituted , 2 or more substituents may be the same or different from each other.

The term'substituted or unsubstituted' in this specification is deuterium; Halogen group; Nitrile group; Nitro group; Hydroxy group; A substituted or unsubstituted alkyl group; A substituted or unsubstituted cycloalkyl group; A substituted or unsubstituted alkoxy group; A substituted or unsubstituted aryloxy group; A substituted or unsubstituted alkenyl group; A substituted or unsubstituted aryl group; And substituted or unsubstituted heterocyclic groups, substituted with one or more substituents selected from the group consisting of substituted or unsubstituted substituents, or having no substituents. For example,'a substituent having two or more substituents' may be a biphenyl group. That is, the biphenyl group may be an aryl group or may be interpreted as a substituent to which two phenyl groups are connected.

In the present specification, examples of the halogen group include fluorine, chlorine, bromine or iodine.

In the present specification, the alkyl group may be straight chain or branched chain, and carbon number is not particularly limited, but is preferably 1 to 50. Specific examples are methyl, ethyl, propyl, n-propyl, isopropyl, butyl, n-butyl, isobutyl, tert-butyl, sec-butyl, 1-methyl-butyl, 1-ethyl-butyl, pentyl, n-pentyl , Isopentyl, neopentyl, tert-pentyl, hexyl, n-hexyl, 1-methylpentyl, 2-methylpentyl, 4-methyl-2-pentyl, 3,3-dimethylbutyl, 2-ethylbutyl, heptyl, n -Heptyl, 1-methylhexyl, cyclopentylmethyl, cyclohexylmethyl, octyl, n-octyl, tert-octyl, 1-methylheptyl, 2-ethylhexyl, 2-propylpentyl, n-nonyl, 2,2-dimethyl Heptyl, 1-ethyl-propyl, 1,1-dimethyl-propyl, isohexyl, 2-methylhexyl, 4-methylhexyl and 5-methylhexyl, but is not limited to these.

In the present specification, the cycloalkyl group is not particularly limited, but preferably has 3 to 60 carbon atoms, specifically cyclopropyl, cyclobutyl, cyclopentyl, 3-methylcyclopentyl, 2,3-dimethylcyclopentyl, cyclohexyl, 3-methylcyclohexyl, 4-methylcyclohexyl, 2,3-dimethylcyclohexyl, 3,4,5-trimethylcyclohexyl, 4-tert-butylcyclohexyl, cycloheptyl and cyclooctyl, and the like. Does not.

In the present specification, the alkoxy group may be a straight chain, branched chain or cyclic chain. The number of carbon atoms of the alkoxy group is not particularly limited, but is preferably 1 to 20 carbon atoms. Specifically, methoxy, ethoxy, n-propoxy, isopropoxy, i-propyloxy, n-butoxy, isobutoxy, tert-butoxy, sec-butoxy, n-pentyloxy, neopentyloxy, Isopentyloxy, n-hexyloxy, 3,3-dimethylbutyloxy, 2-ethylbutyloxy, n-octyloxy, n-nonyloxy, n-decyloxy, benzyloxy and p-methylbenzyloxy, etc. However, it is not limited thereto.

In the present specification, the alkenyl group may be straight chain or branched chain, and carbon number is not particularly limited, but is preferably 2 to 40. Specific examples include vinyl, 1-propenyl, isopropenyl, 1-butenyl, 2-butenyl, 3-butenyl, 1-pentenyl, 2-pentenyl, 3-pentenyl, 3-methyl-1- Butenyl, 1,3-butadienyl, allyl, 1-phenylvinyl-1-yl, 2-phenylvinyl-1-yl, 2,2-diphenylvinyl-1-yl, 2-phenyl-2-( Naphthyl-1-yl)vinyl-1-yl, 2,2-bis(diphenyl-1-yl)vinyl-1-yl, styrenyl group and styrenyl group, and the like, but are not limited thereto.

In the present specification, when the aryl group is a monocyclic aryl group, the number of carbon atoms is not particularly limited, but is preferably 6 to 25 carbon atoms. Specifically, a monocyclic aryl group includes a phenyl group, a biphenyl group and a terphenyl group, but is not limited thereto.

In the present specification, when the aryl group is a polycyclic aryl group, the number of carbon atoms is not particularly limited. It is preferable that it has 10 to 24 carbon atoms. Specifically, polycyclic aryl groups include, but are not limited to, naphthyl group, anthracenyl group, phenanthryl group, pyrenyl group, perylenyl group, chrysenyl group and fluorenyl group.

In the present specification, the fluorenyl group may be substituted, and adjacent substituents may combine with each other to form a ring.

In the present specification, the arylene group means that the aryl group has two bonding positions, that is, a divalent group. These may be applied to the description of the aryl group described above, except that each is a divalent group.

In the present specification, the heterocyclic group includes one or more non-carbon atoms, heteroatoms, and specifically, the heteroatoms may include one or more atoms selected from the group consisting of O, N, Se, and S. The number of carbon atoms in the heterocyclic group is not particularly limited, but is preferably 2 to 60 carbon atoms. Examples of the heterocyclic group include thiophene group, furan group, pyrrol group, imidazole group, thiazole group, oxazole group, oxadiazole group, triazole group, pyridyl group, bipyridyl group, pyrimidyl group, triazine group, triazole group, Acridil group, pyridazine group, pyrazinyl group, quinolinyl group, quinazolinyl group, quinoxalinyl group, isoquinoline group, indole group, carbazole group, benzoxazole group, benzimidazole group, benzothiazole group, benzocarbazole group , Benzothiophene group, dibenzothiophene group, benzofuranyl group, phenanthroline group, thiazolyl group, isooxazolyl group, oxadiazolyl group, thiadiazolyl group, phenothiazinyl group and dibenzo Furanyl groups, and the like, but are not limited to these.

In the present specification, the aryl group of the aryloxy group is the same as the example of the aryl group described above. Specifically, aryloxy groups include phenoxy, p-toryloxy, m-toryloxy, 3,5-dimethyl-phenoxy, 2,4,6-trimethylphenoxy, p-tert-butylphenoxy, and 3-biphenyl Oxy, 4-biphenyloxy, 1-naphthyloxy, 2-naphthyloxy, 4-methyl-1-naphthyloxy, 5-methyl-2-naphthyloxy, 1-anthryloxy, 2-anthryl Oxy, 9-anthryloxy, 1-phenanthryloxy, 3-phenanthryloxy and 9-phenanthryloxy, and the like, but are not limited thereto.

In one embodiment of the present specification, the non-fullerene-based compound may be represented by Formula A below.

[Formula A]

In Chemical Formula A,

Ra to Rf are the same as or different from each other, and each independently hydrogen; Or a substituted or unsubstituted alkyl group,

La to Ld are the same as or different from each other, and each independently an substituted or unsubstituted arylene group; Or a substituted or unsubstituted divalent heterocyclic group,

Ma and Mb are the same as or different from each other, and each independently hydrogen; Halogen group; Or a substituted or unsubstituted alkyl group,

p and q are the same as or different from each other, and each independently an integer of 0 to 2,

When p or q are each 2, the structures in parentheses are the same.

In one embodiment of the present specification, Ra to Rd are each alkyl groups.

In another exemplary embodiment, Ra to Rd are alkyl groups having 1 to 30 carbon atoms, respectively.

In another exemplary embodiment, Ra to Rd are alkyl groups having 1 to 10 carbon atoms, respectively.

In one embodiment of the present specification, Re and Rf are hydrogen.

In one embodiment of the present specification, La to Ld are each arylene groups.

In another exemplary embodiment, La to Ld are arylene groups having 6 to 25 carbon atoms, respectively.

In another exemplary embodiment, La to Ld are phenylene groups.

In another exemplary embodiment, La to Ld are each a divalent heterocyclic group.

In another exemplary embodiment, La to Ld are divalent heterocyclic groups having 2 to 30 carbon atoms, respectively.

In another exemplary embodiment, La to Ld are divalent heterocyclic groups each having 2 to 10 carbon atoms.

In another exemplary embodiment, La to Ld are divalent thiophene groups.

In one embodiment of the present specification, Ma and Mb are hydrogen.

In another exemplary embodiment, Ma and Mb are each an alkyl group.

In another exemplary embodiment, Ma and Mb are alkyl groups having 1 to 10 carbon atoms, respectively.

In another exemplary embodiment, Ma and Mb are methyl groups.

In another exemplary embodiment, Ma and Mb are each a halogen group.

In another exemplary embodiment, Ma and Mb are fluorine.

In one embodiment of the present specification, p and q are each 0.

In another exemplary embodiment, p and q are 1, respectively.

In another exemplary embodiment, p and q are 2, respectively.

In addition, in one embodiment of the present specification, the compound represented by Chemical Formula A may be any one of the following Chemical Formulas A-1 to A-5.

[Formula A-1]

[Formula A-2]

[Formula A-3]

[Formula A-4]

[Formula A-5]

In the present specification, Me means a methyl group.

In one embodiment of the present specification, the non-fullerene-based compound has higher thermal stability than the fullerene-based compound.

In addition, in one embodiment of the present specification, the organic solar cell including the non-fullerene-based compound as an electron acceptor of the photoactive layer and the polymer as an electron donor of the photoactive layer has excellent thermal stability. And the power conversion efficiency is excellent.

The polymer according to the exemplary embodiment of the present specification includes the first unit represented by Chemical Formula 1.

In one embodiment of the present specification, two groups of A1 to A4 are fluorine or chlorine, respectively, and may be substituted at opposite positions of a benzene ring, that is, a para position. In this case, the first unit of fluorine or Chlorine interacts with the S atom of the thiophene of the first unit to increase the planarity of the polymer.

In one embodiment of the present specification, A1 to A4 are the same as or different from each other, and each independently hydrogen, fluorine, or chlorine, and at least one of A1 to A4 is fluorine or chlorine.

In one embodiment of the present specification, at least one of A1 to A4 is fluorine.

In one embodiment of the present specification, two groups of A1 to A4 are fluorine or chlorine, respectively, and the two groups may exist at ortho or para positions with respect to a benzene ring.

In one embodiment of the present specification, A1 and A4 are each fluorine, and A2 and A3 are each hydrogen.

In one embodiment of the present specification, A2 and A3 are each fluorine, and A1 and A4 are each hydrogen.

In one embodiment of the present specification, A1 and A2 are each fluorine, and A3 and A4 are each hydrogen.

In one embodiment of the present specification, A1 is fluorine and A2 to A4 are each hydrogen.

In one embodiment of the present specification, A1 to A4 are each fluorine.

In one embodiment of the present specification, a is 1.

In another exemplary embodiment, b is 1.

In one embodiment of the present specification, R1 is hydrogen.

In another exemplary embodiment, R2 is hydrogen.

In another exemplary embodiment, R3 is hydrogen.

In one embodiment of the present specification, R4 is hydrogen.

The polymer according to the exemplary embodiment of the present specification includes the second unit represented by Chemical Formula 2.

In one embodiment of the present specification, X1 is S.

In one embodiment of the present specification, R10 is hydrogen.

In another exemplary embodiment, R11 is hydrogen.

In one embodiment of the present specification, the second unit represented by Chemical Formula 2 may be represented by Chemical Formula 2-1.

[Formula 2-1]

In Chemical Formula 2-1,

R10 and R11 are the same as defined in the formula (2).

In this case, interaction with the fluorine or chlorine of the first unit represented by Chemical Formula 1 according to an exemplary embodiment of the present specification can be more expected.

The polymer according to the exemplary embodiment of the present specification includes the third unit represented by Chemical Formula 3.

In one embodiment of the present specification, X2 is S.

In another exemplary embodiment, X3 is S.

In one embodiment of the present specification, X4 is S.

In one embodiment of the present specification, Y1 is N.

In another exemplary embodiment, Y2 is N.

In another exemplary embodiment, d is 0.

In another exemplary embodiment, d is 1.

In one embodiment of the present specification, e is 1.

In another exemplary embodiment, e is 0.

In one embodiment of the present specification, Q1 is hydrogen.

In one embodiment of the present specification, Q2 is hydrogen.

In one embodiment of the present specification, Q3 is hydrogen.

In one embodiment of the present specification, Q4 is hydrogen.

In one embodiment of the present specification, R20 and R21 of the third unit represented by Chemical Formula 3 are the same as or different from each other, and each independently substituted or unsubstituted alkoxy group; Or a substituted or unsubstituted aryloxy group. In this case, the O atom of R20 and R21; Fluorine or chlorine of the first unit represented by Formula 1; And S atoms of the second unit represented by Chemical Formula 2 interact with each other to improve intermolecular packing.

Therefore, when the polymer according to the exemplary embodiment of the present specification is included, it is possible to induce an increase in the fill factor (FF), thereby providing a device with high efficiency.

In the present specification, the interaction means a non-covalent interaction in which chemical structures or atoms constituting the chemical structure are affected and influenced by an action other than a covalent bond with each other, for example, a chalcogen bond. can do.

The polymer according to the exemplary embodiment of the present specification minimizes the torsion angle of the backbone of the polymer through interaction of non-covalent bonds with other units within or adjacent to the unit, thereby improving the flatness of the polymer. Can. In addition, the non-covalent interaction improves pi-pi stacking, thereby improving charge mobility due to delocalization of polaron and exiton, and packaging (packing) has an easy effect.

In one embodiment of the present specification, R20 and R21 are the same as or different from each other, and each independently an substituted or unsubstituted alkoxy group.

In another exemplary embodiment, R20 and R21 are the same as or different from each other, and each independently an substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms.

In another exemplary embodiment, R20 and R21 are the same as or different from each other, and each independently a substituted or unsubstituted dodecyloxy group.

In one embodiment of the present specification, R20 and R21 are dodecyloxy groups.

In one embodiment of the present specification, R20 and R21 are ethylhexyloxy groups.

In one embodiment of the present specification, the third unit represented by Chemical Formula 3 is represented by the following Chemical Formula 3-1 or Chemical Formula 3-2.

[Formula 3-1]

[Formula 3-2]

In Chemical Formulas 3-1 and 3-2,

R20 and R21 are the same as defined in Chemical Formula 3.

In one embodiment of the present specification, the polymer includes a unit represented by Chemical Formula 4 below.

[Formula 4]

In Chemical Formula 4,

l is the molar fraction, and is a real number with 0 <l <1,

m is the molar fraction, 0 <m <1 is a real number,

l+m = 1,

A is the first unit represented by Formula 1,

B is a second unit represented by Chemical Formula 2,

C and C'are the same as or different from each other, and each independently a third unit represented by Chemical Formula 3,

n is a repetition number of units, and is an integer of 1 to 10,000.

In one embodiment of the present specification, A in Chemical Formula 4 is a first unit represented by Chemical Formula 1, and a and b are each independently an integer of 1 to 3, preferably 1.

In one embodiment of the present specification, B in Chemical Formula 4 is a second unit represented by Chemical Formula 2-1.

In one embodiment of the present specification, C and C'in Chemical Formula 4 are third units represented by Chemical Formula 3-1.

In one embodiment of the present specification, the polymer includes a unit represented by any one of the following Chemical Formulas 5-1 to 5-4.

[Formula 5-1]

[Formula 5-2]

[Formula 5-3]

[Formula 5-4]

In Chemical Formulas 5-1 to 5-4,

R22 to R25 are the same as or different from each other, and each independently a substituted or unsubstituted alkyl group; Or a substituted or unsubstituted aryl group,

R26 to R31 are the same as or different from each other, and each independently hydrogen; Or a substituted or unsubstituted alkyl group,

A1 to A4 are the same as defined in Formula 1,

l is the molar fraction, 0 <l <1 is a real number,

m is the molar fraction, and is a real number with 0 <m <1,

l+m = 1,

n is a repetition number of units, and is an integer of 1 to 10,000.

In one embodiment of the present specification, R22 to R25 are each an alkyl group.

In another exemplary embodiment, R22 to R25 are alkyl groups having 1 to 15 carbon atoms, respectively.

In another exemplary embodiment, R22 to R25 are alkyl groups having 1 to 15 carbon atoms, respectively.

In another exemplary embodiment, R22 to R25 are each a dodecyl group.

In another exemplary embodiment, R22 to R25 are each an ethylhexyl group.

In one embodiment of the present specification, R26 to R31 are hydrogen.

In one embodiment of the present specification, A1 to A4 are each fluorine.

In one embodiment of the present specification, l is 0.5.

In another exemplary embodiment, m is 0.5.

In one embodiment of the present specification, the polymer includes a unit represented by any one of the following Chemical Formulas 6-1 to 6-5.

[Formula 6-1]

[Formula 6-2]

[Formula 6-3]

[Formula 6-4]

[Formula 6-5]

In one embodiment of the present specification, the polymer is a random polymer. In addition, in the case of a random polymer, solubility is improved, and there is an economical effect in time and cost in the device manufacturing process.

In one embodiment of the present specification, the terminal group of the polymer is a substituted or unsubstituted heterocyclic group; Or a substituted or unsubstituted aryl group.

In one embodiment of the present specification, the terminal group of the polymer is a 4-(trifluoromethyl)phenyl (4-(trifluoromethyl)phenyl) group.

In one embodiment of the present specification, the terminal group of the polymer is a bromo-thiophene group.

In another exemplary embodiment, the terminal group of the polymer is a trifluoro-benzene group.

In one embodiment of the present specification, the electron donor is a first unit represented by Formula 1; A second unit represented by Formula 2; And a third unit represented by Formula 3, wherein the electron acceptor is a non-fullerene compound.

In another exemplary embodiment, the electron donor is a polymer including a unit represented by Chemical Formula 5, and the electron acceptor is a compound represented by Chemical Formula A-1.

In one embodiment of the present specification, the mass ratio of the electron donor and the electron acceptor is 1:1 to 1:4. Preferably, it is 1:1.5 to 1:2.5, and more preferably 1:1.8 to 1:2.2.

According to one embodiment of the present specification, the number average molecular weight of the polymer is preferably 5,000 g/mol to 1,000,000 g/mol.

According to an exemplary embodiment of the present specification, the polymer may have a molecular weight distribution of 1 to 10. Preferably, the polymer has a molecular weight distribution of 1 to 3.

The lower the molecular weight distribution and the larger the number average molecular weight, the better the electrical and mechanical properties.

In addition, it is preferable that the number average molecular weight is 100,000 g/mol or less in order to have a solubility of a certain level or more, so that application of the solution coating method is advantageous.

The polymer may be prepared by adding monomers of each unit to chlorobenzene as a solvent, putting together Pd ₂ (dba) ₃ and P(o-tolyl) _3, and polymerizing them in a microwave reactor.

The polymer according to the present specification can be prepared by a multi-step chemical reaction. After preparing the monomers through an alkylation reaction, a Grignard reaction, a Suzuki coupling reaction, and a Stille coupling reaction, a final polymer is obtained through a carbon-carbon coupling reaction such as a steel coupling reaction. You can manufacture them. When the substituent to be introduced is a boronic acid or a boronic ester compound, it can be prepared through a Suzuki coupling reaction, and the substituent to be introduced is tributyltin or trimethyltin ) In the case of a compound, it may be prepared through a steel coupling reaction, but is not limited thereto.

The organic solar cell according to the exemplary embodiment of the present specification includes a first electrode, a photoactive layer, and a second electrode. The organic solar cell may further include a substrate, a hole transport layer and/or an electron transport layer.

In an exemplary embodiment of the present specification, when the organic solar cell receives photons from an external light source, electrons and holes are generated between the electron donor and the electron acceptor. The generated holes are transported to the anode through the electron donor layer.

In one embodiment of the present specification, the organic solar cell may further include an additional organic material layer. The organic solar cell may reduce the number of organic material layers by using organic materials having multiple functions simultaneously.

In one embodiment of the present specification, the first electrode is an anode, and the second electrode is a cathode. In another exemplary embodiment, the first electrode is a cathode, and the second electrode is an anode.

In one embodiment of the present specification, the organic solar cell may be arranged in order of cathode, photoactive layer and anode, or may be arranged in order of anode, photoactive layer and cathode, but is not limited thereto.

In another exemplary embodiment, the organic solar cell may be arranged in the order of an anode, a hole transport layer, a photoactive layer, an electron transport layer, and a cathode, or may be arranged in the order of a cathode, an electron transport layer, a photoactive layer, a hole transport layer, and an anode. , But is not limited to this.

1 is a view showing an organic solar cell according to an exemplary embodiment of the present disclosure, including an anode 101, a hole transport layer 102, a photoactive layer 103 and the cathode 104.

In one embodiment of the present specification, the organic solar cell has a normal structure. In the normal structure, a substrate, a first electrode, a hole transport layer, an organic material layer including a photoactive layer, an electron transport layer, and a second electrode may be stacked in this order.

In one embodiment of the present specification, the organic solar cell has an inverted structure. In the inverted structure, a substrate, a first electrode, an electron transport layer, an organic material layer including a photoactive layer, a hole transport layer, and a second electrode may be stacked in this order.

In one embodiment of the present specification, the first electrode is an anode, and the second electrode is a cathode. In another exemplary embodiment, the first electrode is a cathode, and the second electrode is an anode.

In one embodiment of the present specification, the organic solar cell has a tandem structure. In this case, the organic solar cell may include two or more photoactive layers. In the organic solar cell according to the exemplary embodiment of the present specification, the photoactive layer may be one layer or two or more layers.

In another exemplary embodiment, a buffer layer may be provided between the photoactive layer and the hole transport layer or between the photoactive layer and the electron transport layer. At this time, a hole injection layer may be further provided between the anode and the hole transport layer. Further, an electron injection layer may be further provided between the cathode and the electron transport layer.

In one embodiment of the present specification, the electron donor and the electron acceptor constitute a bulk heterojunction (BHJ).

The bulk heterojunction means that the electron donor material and the electron acceptor material are mixed with each other in the photoactive layer.

In one embodiment of the present specification, the photoactive layer further includes an additive.

In one embodiment of the present specification, the molecular weight of the additive is 50 g/mol to 300 g/mol.

In another exemplary embodiment, the boiling point of the additive is an organic material of 30 ℃ to 300 ℃.

In the present specification, the organic material means a material containing at least one carbon atom.

In one embodiment, the additive is 1,8-diiodooctane (DIO:1,8-diiodooctane), 1-chloronaphthalene (1-CN:1-chloronaphthalene), diphenyl ether (DPE:diphenylether) , Octane dithiol (octane dithiol) and tetrabromothiophene (tetrabromothiophene) may further include one or two additives selected from the group consisting of.

In one embodiment of the present specification, the photoactive layer is a bilayer structure including an n-type organic material layer and a p-type organic material layer, and the p-type organic material layer includes the polymer.

In the present specification, the substrate may be a glass substrate or a transparent plastic substrate having excellent transparency, surface smoothness, ease of handling, and waterproofness, but is not limited thereto, and is not limited if it is a substrate commonly used in organic solar cells. Specifically, there are glass or PET (polyethylene terephthalate), PEN (polyethylene naphthalate), PP (polypropylene), PI (polyimide) and TAC (triacetyl cellulose). It is not limited to this.

The material of the first electrode may be a material that is transparent and has excellent conductivity, but is not limited thereto. Metals such as vanadium, chromium, copper, zinc, gold or alloys thereof; Metal oxides such as zinc oxide, indium oxide, indium tin oxide (ITO), and indium zinc oxide (IZO); A combination of metal and oxide such as ZnO:Al or SnO ₂ :Sb; And conductive polymers such as poly(3-methylthiophene), poly[3,4-(ethylene-1,2-dioxy)thiophene] (PEDOT), polypyrrole and polyaniline, but is not limited thereto. .

The method for forming the first electrode is not particularly limited, and for example, sputtering, E-beam, thermal deposition, spin coating, screen printing, inkjet printing, doctor blade or gravure printing may be used.

When the first electrode is formed on a substrate, it may undergo cleaning, water removal, and hydrophilic modification processes.

For example, the patterned ITO substrate is sequentially washed with a cleaning agent, acetone, and isopropyl alcohol (IPA), and then heated at 100° C. to 150° C. for 1 to 30 minutes, preferably 120° C. for 10 minutes to remove moisture. When dried and the substrate is completely cleaned, the surface of the substrate is modified to be hydrophilic.

Through the above surface modification, the junction surface potential can be maintained at a level suitable for the surface potential of the photoactive layer. In addition, it is easy to form a polymer thin film on the first electrode during modification, and the quality of the thin film may be improved.

Pretreatment techniques for the first electrode include: a) a surface oxidation method using a parallel plate discharge, b) a method of oxidizing the surface through ozone generated using UV ultraviolet rays in a vacuum, and c) oxygen generated by plasma And oxidation using a radical.

One of the above methods can be selected according to the state of the first electrode or the substrate. However, regardless of which method is commonly used, it is preferable to prevent oxygen escape from the surface of the first electrode or the substrate and to suppress the residual of moisture and organic substances as much as possible. At this time, the practical effect of the pretreatment can be maximized.

As a specific example, a method of oxidizing the surface through ozone generated using UV may be used. At this time, after the ultrasonic cleaning, the patterned ITO substrate is baked on a hot plate to dry it well, and then put into a chamber, and by operating a UV lamp, the oxygen gas reacts with UV light to generate ozone. The patterned ITO substrate can be cleaned.

However, the method of surface modification of the patterned ITO substrate in the present specification is not particularly limited, and any method may be used as long as it is a method of oxidizing the substrate.

The second electrode may be a metal having a small work function, but is not limited thereto. Metals such as magnesium, calcium, sodium, potassium, titanium, indium, yttrium, lithium, gadolinium, aluminum, silver, tin and lead or alloys thereof; Alternatively, a material having a multilayer structure such as LiF/Al, LiO ₂ /Al, LiF/Fe, Al:Li, Al:BaF ₂ or Al:BaF ₂ :Ba may be used, but is not limited thereto.

The second electrode may be formed by being deposited inside a thermal evaporator showing a vacuum of 5x10 ^-7 torr or less, but is not limited to this method.

The hole transport layer and/or electron transport layer material plays a role of efficiently transferring electrons and holes separated from the photoactive layer to the electrode, and does not specifically limit the material.

The hole transport layer material is PEDOT:PSS(Poly(3,4-ethylenediocythiophene) doped with poly(styrenesulfonic acid)); Molybdenum oxide (MoO _x ); Vanadium oxide (V ₂ O ₅ ); Nickel oxide (NiO); Or it may be a tungsten oxide (WO _x ) and the like, but is not limited thereto.

The electron transport layer material may be electron-extracting metal oxides, specifically, a metal complex of 8-hydroxyquinoline; Complexes including Alq ₃ ; Metal complexes including Liq; LiF; Ca; Titanium oxide (TiO _x ); Zinc oxide (ZnO); Or it may be cesium carbonate (Cs ₂ CO ₃ ) and the like, but is not limited thereto.

The photoactive layer may be formed by dissolving a photoactive material such as an electron donor and/or an electron acceptor in an organic solvent, and then forming a solution by spin coating, dip coating, screen printing, spray coating, doctor blade and brush painting. It is not limited to the method.

Hereinafter, examples will be described in detail to specifically describe the present specification. However, the embodiments according to the present specification may be modified in various other forms, and the scope of the present specification is not interpreted to be limited to the embodiments described below. The embodiments of the present specification are provided to more fully describe the present specification to those skilled in the art.

< Manufacturing example >

Preparation Example 1 Synthesis of Polymer 1

(1) Synthesis of Formula J

(Formula J)

After adding toluene to the two starting materials, adding 0.05 equivalents of tetrakis(triphenylphosphine)palladium(0)(Pd(PPh ₃ ) ₄ ), stirring at 80°C for 15 hours, the reaction solution gradually turned black. Changed. This was worked up, dried with magnesium sulfate, and recrystallized to obtain formula J (white powder, 4.3 g).

The synthesized NMR spectrum of Formula J is shown in FIG. 4.

(2) Synthesis of Formula J-1 (first unit)

(Formula J) (Formula J-1)

After dissolving the prepared formula (J) in tetrahydrofuran (THF) and lowering the temperature to -78°C, 2.1 equivalents of n-butyllithium (n-BuLi) was added and stirred for 30 minutes. After this, the solution color was changed to yellow after further stirring at room temperature for 1 hour. Again, the temperature was lowered to -78°C, 2.1 equivalents of trimethyltin chloride was added, and the mixture was stirred for 12 hours while slowly raising the temperature to room temperature. After 12 hours, the color of the solution changed to an ocher color, and when re-crystallized after work up, it was possible to obtain the chemical formula J-1 in the form of a glossy yellow solid.

The synthesized NMR spectrum of Formula J-1 is shown in FIG. 5.

(3) Synthesis of Formula K (second unit)

After adding 2,5-dibromothiophene (2,5-Dibromothiophene, 9.68 g, 40.0 mmol) to 200 ml of tetrahydrofuran (THF), the temperature was lowered to -78°C. At this temperature, 1.6M n-BuLi (1.6M n-Butyllithium in hexane, 55ml, 88mmol) dissolved in hexane was slowly added and stirred for 1 hour. After that, 1M trimethyltinchloride (1M Trimethyltinchloride in THF, 100ml, 100mmol) dissolved in THF was added at once and the temperature was raised to room temperature and stirred for 12 hours. The solution was poured into ice, extracted three times with diethyl ether, washed three times with water, and residual water was removed with magnesium sulfate (MgSO ₄ : Magnesium sulfate). The remaining solution was removed under reduced pressure and recrystallized with methanol to obtain a white solid.

Yield: 73.1%

Figure 6 shows the NMR spectrum of the synthesized formula K.

(4) Synthesis of Formula L (third unit)

The compound of Formula L was synthesized based on JOURNAL OF POLYMER SCIENCE PART A: POLYMER CHEMISTRY 2011, 49, 4387-4397, 4389.

(5) Synthesis of Polymer 1

The monomers of the first to third units were chlorobenzene as a solvent, added together with Pd ₂ (dba) ₃ and P(o-tolyl) _3, and polymerized in a microwave reactor to prepare Polymer 1 below.

[Polymer 1]

The properties of the polymer 1 are shown in Table 1 below.

Mn
(Number average molecular weight) Mw (weight average molecular weight) PDI (molecular weight distribution, Mw/Mn) UV _edge (Energy band gap on film) 21,315 24,970 1.17 685.12 UV _(s) (UV on solution _max ) UV _(f)
(UV on film _max ) HOMO energy level LUMO energy level 1.82 1.81 5.53 3.72

Preparation Example 2 Synthesis of Polymer 2

(1) Synthesis of Formula M

After adding toluene to the two starting materials, adding 0.05 equivalents of tetrakis(triphenylphosphine)palladium(0)(Pd(PPh ₃ ) ₄ ), stirring at 80°C for 15 hours, the reaction solution gradually turned black. Changed. This was worked up, dried with magnesium sulfate, and recrystallized to obtain the formula M (white powder, 4.3 g).

(2) Synthesis of Formula M-1 (first unit)

Dissolve the prepared formula M in tetrahydrofuran (THF), lower the temperature to -78°C, add 2.1 equivalent of n-butyllithium (n-BuLi) and stir for 30 minutes. After this, the solution color was changed to yellow after further stirring at room temperature for 1 hour. Again, the temperature was lowered to -78°C, 2.1 equivalents of trimethyltin chloride was added, and the mixture was stirred for 12 hours while slowly raising the temperature to room temperature. After 12 hours, the color of the solution changed to ocher color, and when re-crystallized after work up, it was possible to obtain the formula M-1 in the form of a glossy yellow solid.

(3) Synthesis of Formula K (second unit)

Formula K was synthesized in the same manner as in (3) of Preparation Example 1.

(4) Synthesis of Formula L (third unit)

Formula L was synthesized in the same process as in Preparation Example 1 (4).

(5) Synthesis of Polymer 2

The monomers of the first to third units were chlorobenzene as a solvent, put together with Pd ₂ (dba) ₃ and P(o-tolyl) _3, and polymerized in a microwave reactor to prepare Polymer 2 below.

[Polymer 2]

The properties of the polymer 2 are shown in Table 2 below.

Preparation Example 3 Synthesis of Polymer 3

(1) Synthesis of Formula N

After adding toluene to the two starting materials, adding 0.05 equivalents of tetrakis(triphenylphosphine)palladium(0)(Pd(PPh ₃ ) ₄ ), stirring at 80°C for 15 hours, the reaction solution gradually turned black. Changed. This was worked up, dried with magnesium sulfate, and recrystallized to obtain the formula N (white powder, 4.3 g).

(2) Synthesis of Formula N-1 (First Unit)

Dissolve the prepared formula N in tetrahydrofuran (THF), lower the temperature to -78°C, add 2.1 equivalent of n-butyllithium (n-BuLi) and stir for 30 minutes. After this, the solution color was changed to yellow after further stirring at room temperature for 1 hour. Again, the temperature was lowered to -78°C, 2.1 equivalents of trimethyltin chloride was added, and the mixture was stirred for 12 hours while slowly raising the temperature to room temperature. After 12 hours, the color of the solution changed to ocher color, and when re-crystallized after work up, it was possible to obtain the formula N-1 in the form of a glossy yellow solid.

(3) Synthesis of Formula K (second unit)

Formula K was synthesized in the same manner as in (3) of Preparation Example 1.

(4) Synthesis of Formula L (third unit)

Formula L was synthesized in the same process as in Preparation Example 1 (4).

(5) Synthesis of Polymer 3

The monomers of the first to third units were chlorobenzene as a solvent, put together with Pd2(dba)3 and P(o-tolyl)3, and polymerized in a microwave reactor to prepare Polymer 3 below.

[Polymer 3]

The properties of the polymer 3 are shown in Table 2 below.

Preparation Example 4 Synthesis of Polymer 4

(1) Synthesis of Formula O

After adding toluene to the two starting materials, adding 0.05 equivalents of tetrakis(triphenylphosphine)palladium(0)(Pd(PPh ₃ ) ₄ ), stirring at 80°C for 15 hours, the reaction solution gradually turned black. Changed. This was worked up, dried with magnesium sulfate, and recrystallized to obtain formula O (white powder, 4.3 g).

(2) Synthesis of Formula O-1 (First Unit)

After dissolving the prepared formula (O) in tetrahydrofuran (THF) and lowering the temperature to -78°C, 2.1 equivalents of n-butyllithium (n-BuLi) was added and stirred for 30 minutes. After this, the solution color was changed to yellow after further stirring at room temperature for 1 hour. Again, the temperature was lowered to -78°C, 2.1 equivalents of trimethyltin chloride was added, and the mixture was stirred for 12 hours while slowly raising the temperature to room temperature. After 12 hours, the color of the solution changed to an ocher color, and when re-crystallized after work up, it was possible to obtain the formula O-1 in the form of a glossy yellow solid.

(3) Synthesis of Formula K (second unit)

Formula K was synthesized in the same manner as in (3) of Preparation Example 1.

(4) Synthesis of Formula L (third unit)

Formula L was synthesized in the same process as in Preparation Example 1 (4).

(5) Synthesis of Polymer 4

The monomers of the first to third units were chlorobenzene as a solvent, put together with Pd2(dba)3 and P(o-tolyl)3, and polymerized in a microwave reactor to prepare Polymer 4 below.

[Polymer 4]

The properties of the polymer 4 are shown in Table 2 below.

Preparation Example 5 Synthesis of Polymer 5

(1) Synthesis of Formula J

Formula (J) was synthesized in the same manner as in (1) of Preparation Example 1.

(2) Synthesis of Formula J-1 (first unit)

Formula (J-1) was synthesized in the same manner as in (2) of Preparation Example 1.

(3) Synthesis of Formula K (second unit)

Formula K was synthesized in the same manner as in (3) of Preparation Example 1.

(4) Synthesis of Formula P (3rd Unit)

The compound of formula P is Journal of Materials Chemistry A: Materials for Energy and Sustainability, 4(47), 18585-18597; Synthesized based on 2016.

(5) Synthesis of Polymer 5

The monomers of the first to third units were chlorobenzene as a solvent, put together with Pd2(dba)3 and P(o-tolyl)3, and polymerized in a microwave reactor to prepare Polymer 5 below.

[Polymer 5]

The properties of the polymer 5 are shown in Table 2 below.

Mn
(Number average molecular weight) Mw
(Weight average molecular weight) PDI (molecular weight distribution, Mw/Mn) UV _edge (Energy band gap on film) Polymer 2 23,000 31,000 1.348 680 Polymer 3 21,000 26,000 1.238 678 Polymer 4 22,400 27,800 1.24 688 Polymer 5 20,500 24,700 1.205 681

<Example: Preparation of an organic solar cell>

Example 1-1.

Polymer 1 and The following ITIC (Solarmer Materials, Inc.) was dissolved in 2 ml of chlorobenzene (CB) at a ratio of 1:2 to prepare a composite solution, wherein the concentration of the composite solution was adjusted to 2.0 wt% and organic The solar cell has a structure of ITO/PEDOT:PSS/photoactive layer/Al (anode/hole transport layer/photoactive layer/cathode). A glass substrate coated with a bar type of 1.5 x 1.5 cm ² is ultrasonically cleaned using distilled water, acetone and 2-propanol, ozonized on the ITO surface for 10 minutes, and then 45 nm thick PEDOT:PSS (AI4083) was spin-coated and heat-treated at 235°C for 5 minutes. For coating the photoactive layer, polymer 1 and the ITIC composite solution were spin-coated at 1,500 rpm for 10 seconds, and Al was added at a rate of 1 Å/s at a thickness of 100 nm using a thermal evaporator under a 3x10 ^-8 torr vacuum. It was deposited to prepare an organic solar cell.

[ITIC]

Example 1-2.

An organic solar cell was manufactured in the same manner as in Example 1-1, except that the composite solution of Polymer 1 and ITIC in Example 1-1 was spin-coated at 2,000 rpm for 10 seconds.

Example 1-3.

An organic solar cell was manufactured in the same manner as in Example 1-1, except that the composite solution of Polymer 1 and ITIC in Example 1-1 was spin-coated at 2,500 rpm for 10 seconds.

Examples 2-1 to 2-3.

Organic solar cells were prepared in the same manner as in Examples 1-1 to 1-3, except that Polymer 2 synthesized in Preparation Example 2 was used instead of Polymer 1 in Examples 1-1 to 1-3.

Examples 3-1 to 3-3.

Organic solar cells were manufactured in the same manner as in Examples 1-1 to 1-3, except that Polymer 3 synthesized in Preparation Example 3 was used instead of Polymer 1 in Examples 1-1 to 1-3, respectively.

Examples 4-1 to 4-3.

Organic solar cells were prepared in the same manner as in Examples 1-1 to 1-3, except that Polymer 4 synthesized in Preparation Example 4 was used instead of Polymer 1 in Examples 1-1 to 1-3.

Examples 5-1 to 5-3.

Organic solar cells were manufactured in the same manner as in Examples 1-1 to 1-3, except that Polymer 5 synthesized in Preparation Example 5 was used instead of Polymer 1 in Examples 1-1 to 1-3.

Comparative Example 1.

In Example 1-1, instead of the composite solution of Polymer 1 and ITIC, the following PTB7-Th and the ITIC were dissolved in 25 mg/ml of orthodichlorobenzene (ODCB) at a ratio of 1:1.3 to use the composite solution. An organic solar cell was manufactured in the same manner as in Example 1-1, except for that.

[PTB7-Th]

Comparative Example 2.

An organic solar cell was manufactured in the same manner as in Comparative Example 1, except that the composite solution of PTB7-Th and ITIC in Comparative Example 1 was spin-coated at 1,200 rpm for 10 seconds.

Comparative Example 3-1.

In Example 1-1, instead of Polymer 1 and ITIC, Polymer 1 and PCBM were dissolved at a ratio of 1:1 to prepare a composite solution, and the concentration was adjusted to 2.5 wt%, and the spin coating speed of the composite solution was 1,000 rpm. An organic solar cell was manufactured in the same manner as in Example 1-1 except for the change.

[PCBM]

Comparative Example 3-2.

An organic solar cell was manufactured in the same manner as in Comparative Example 3-1, except that the spin coating speed of the composite solution in Comparative Example 3-1 was changed to 1.500 rpm.

Comparative Example 3-3.

An organic solar cell was manufactured in the same manner as in Comparative Example 3-1, except that the spin coating speed of the composite solution was changed to 2.000 rpm in Comparative Example 3-1.

The photoelectric conversion characteristics of the organic solar cells prepared in Examples and Comparative Examples were measured under 100 mW/cm ² (AM 1.5) conditions, and the results are shown in Table 3 below.

Photoactive layer Deposition rate
(rpm) V _OC
(V) J _SC (mA/cm ² ) FF PCE
(%) Example 1-1 Polymer 1: ITIC = 1:2 1,500 0.933 13.582 0.586 7.43 Example 1-2 2,000 0.931 12.810 0.607 7.24 Example 1-3 2,500 0.921 11.043 0.595 6.06 Example 2-1 Polymer 2: ITIC = 1:2 1,500 0.914 13.119 0.618 7.41 Example 2-2 2,000 0.916 13.180 0.621 7.50 Example 2-3 2,500 0.907 12.762 0.597 6.91 Example 3-1 Polymer 3: ITIC = 1:2 1,500 0.938 13.007 0.587 7.16 Example 3-2 2,000 0.932 13.197 0.583 7.17 Example 3-3 2,500 0.925 12.076 0.566 6.32 Example 4-1 Polymer 4: ITIC = 1:2 1,500 0.919 13.054 0.569 6.82 Example 4-2 2,000 0.924 13.258 0.578 7.08 Example 4-3 2,500 0.913 12.538 0.568 6.50 Example 5-1 Polymer 5: ITIC = 1:2 1,500 0.916 13.335 0.595 7.27 Example 5-2 2,000 0.905 13.639 0.586 7.23 Example 5-3 2,500 0.901 12.889 0.598 6.95 Comparative Example 1 PTB7-Th: ITIC = 1:1.3 1,500 0.640 10.381 0.530 3.52 Comparative Example 2 1,200 0.623 11.267 0.426 2.99 Comparative Example 3-1 Polymer 1: PCBM = 1:1 1,000 0.869 9.361 0.608 4.95 Comparative Example 3-2 1,500 0.876 9.872 0.651 5.63 Comparative Example 3-3 2,000 0.876 9.050 0.661 5.24

2 is a view showing the current density according to the voltage of the organic solar cells of Examples 1-1 to 1-3, and FIG. 3 is a view showing the current density according to the voltage of the organic solar cells of Comparative Examples 1 and 2. In Table 3, Voc is an open voltage, Jsc is a short-circuit current, FF is a fill factor, and PCE is an energy conversion efficiency. The open voltage and short-circuit current are the X-axis section and the Y-axis section in the quadrant of the voltage-current density curve, respectively, and the higher these two values, the higher the efficiency of the solar cell is. In addition, the fill factor is a value obtained by dividing the area of the rectangle that can be drawn inside the curve by the product of the short-circuit current and the open voltage. The energy conversion efficiency can be obtained by dividing these three values by the intensity of the irradiated light. The higher the value, the better.

In Table 3, the organic solar cell comprising the polymer according to an exemplary embodiment of the present invention as an electron donor and a non-fullerene compound as an electron acceptor includes an organic sun including PTB7-Th of Comparative Examples 1 and 2 as an electron donor. It can be seen that the open voltage is higher, the device efficiency is excellent, and the energy conversion efficiency is higher than the organic solar cell including the battery and the fullerene compounds of Comparative Examples 3-1 to 3-3 as an electron acceptor. Specifically, it can be seen that the energy conversion efficiency of the present example is 6% or more, preferably 7% or more, whereas the energy conversion efficiency of the comparative example is measured to be less than 6%.

101: anode (ITO)
102: hole transport layer (PEDOT: PSS)
103: photoactive layer
104: cathode (Al)

Claims (9)

A first electrode;
A second electrode provided to face the first electrode; And
It is provided between the first electrode and the second electrode, and includes at least one organic layer including a photoactive layer,
The photoactive layer includes an electron donor and an electron acceptor,
The mass ratio of the electron donor and the electron acceptor is 1:1.8 to 1:2.2,
The electron donor is a first unit represented by the following formula (1); A second unit represented by Formula 2 below; And it includes a polymer comprising a third unit represented by the formula (3),
The electron acceptor is an organic solar cell comprising a non-fullerene (non-fullerene)-based compound:
[Formula 1]

[Formula 2]

[Formula 3]

In Chemical Formulas 1 to 3,
X1 to X4 are each S,
Y1 and Y2 are each N,
Q1 to Q4, R1 to R4, R10 and R11 are each hydrogen,
R20 and R21 are the same as or different from each other, and each independently an alkoxy group having 1 to 20 carbon atoms,
a and b are the same as or different from each other, and each is an integer from 1 to 3,
d and e are the same as or different from each other, each being an integer from 0 to 3,
A1 to A4 are the same as or different from each other, and each independently, hydrogen, fluorine or chlorine, and at least one of A1 to A4 is fluorine or chlorine. The method according to claim 1,
The non-fullerene-based compound is an organic solar cell represented by the following Chemical Formula A:
[Formula A]

In the above formula A,
Ra to Rd are the same as or different from each other, and each independently an alkyl group having 1 to 30 carbon atoms,
Re and Rf are each hydrogen,
La to Ld are the same as or different from each other, and each independently an arylene group having 6 to 25 carbon atoms; Or a divalent thiophene group,
Ma and Mb are the same as or different from each other, and each independently hydrogen; Halogen group; Or an alkyl group having 1 to 10 carbon atoms,
p and q are the same as or different from each other, and each independently an integer of 0 to 2,
When p or q are each 2, the structures in parentheses are the same. The method according to claim 2,
The compound represented by Chemical Formula A is any one of the following Chemical Formulas A-1 to A-5:
[Formula A-1]

[Formula A-2]

[Formula A-3]

[Formula A-4]

[Formula A-5]

delete The method according to claim 1,
The third unit represented by Chemical Formula 3 is an organic solar cell represented by Chemical Formula 3-1 or Chemical Formula 3-2:
[Formula 3-1]

[Formula 3-2]

In Chemical Formulas 3-1 and 3-2,
R20 and R21 are the same as defined in Chemical Formula 3. The method according to claim 1,
The polymer is an organic solar cell comprising a unit represented by the following formula (4):
[Formula 4]

In Chemical Formula 4,
l is the molar fraction, and is a real number with 0 <l <1,
m is the molar fraction, 0 <m <1 is a real number,
l+m = 1,
A is the first unit represented by Formula 1,
B is a second unit represented by Chemical Formula 2,
C and C'are the same or different from each other, and each independently a third unit represented by Chemical Formula 3,
n is a repetition number of units, and is an integer of 1 to 10,000. The method according to claim 1,
The polymer is an organic solar cell comprising a unit represented by any one of the following formulas 5-1 to 5-4:
[Formula 5-1]

[Formula 5-2]

[Formula 5-3]

[Formula 5-4]

In Chemical Formulas 5-1 to 5-4,
R22 to R25 are the same as or different from each other, and each independently an alkyl group having 1 to 15 carbon atoms,
R26 to R31 are each hydrogen,
A1 to A4 are the same as defined in Formula 1,
l is the molar fraction, 0 <l <1 is a real number,
m is the molar fraction, and is a real number with 0 <m <1,
l+m = 1,
n is a repetition number of units, and is an integer of 1 to 10,000. The method according to claim 1,
The polymer is an organic solar cell comprising a unit represented by any one of the following formulas 6-1 to 6-5:
[Formula 6-1]

[Formula 6-2]

[Formula 6-3]

[Formula 6-4]

[Formula 6-5]

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